title: Activity size distribution of some natural radionuclides.
abstract: In this study, the results concerning the activity size distribution of the long-lived ((210)Pb) radon decay product aerosols and the thoron decay product aerosols ((212)Pb) and ((7)Be) of the outdoor atmosphere are presented. Also, the mass size distribution of the aerosol particles is determined. The low-pressure Berner cascade impactor Model 20/0.015 was used as a sampling device. The activity size distribution of these radionuclides was determined by one log-normal distribution (accumulation mode) whereas the mass size distribution was by two log-normal distributions (accumulation and coarse mode). The activity median aerodynamic diameter (AMAD) of (212)Pb was found to be 305 nm with a geometric standard deviation (σg) of 2.41. The specific air activity concentration of (212)Pb was found to be 0.14 ± 0.012 Bq m(-3). An AMAD of (210)Pb of 610 nm with σg of 1.8 was determined, whereas that of 550 nm with σg of 1.97 was determined for (7)Be. The specific air activity concentration of (210)Pb and (7)Be was found to be 0.0016±2.5×10(-4) and 0.00348 ± 4×10(-4) Bq m(-3), respectively. Using a dosimetric model, the total deposition fraction as well as the total equivalent dose has been evaluated considering the observed parameters of the activity size distribution of (212)Pb. At a total deposition fraction of ∼21 %, the total equivalent dose was found to be 0.41 µSv.
authors.affiliation: Physics Department, Faculty of Science, North Jeddah, King Abdulaziz University, Kingdom of Saudi Arabia.
authors.forename: M
authors.initials: M
authors.lastname: Mohery
authors.forename: A M
authors.initials: AM
authors.lastname: Abdallah
authors.forename: Z M
authors.initials: ZM
authors.lastname: Al-Amoudi
authors.forename: S S
authors.initials: SS
authors.lastname: Baz
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000396:Air Pollutants, Radioactive / Q000032:analysis; D016902:Air Pollution, Indoor / Q000032:analysis*; D001272:Atmosphere; D007856:Lead Radioisotopes / Q000032:analysis; D010316:Particle Size; D011834:Radiation Monitoring / Q000379:methods*; D011868:Radioisotopes / Q000032:analysis*; D011874:Radiometry / Q000379:methods*; D011886:Radon / Q000032:analysis*; D017687:Radon Daughters / Q000032:analysis; D012529:Saudi Arabia
chemical_list: D000336:Aerosols; D000396:Air Pollutants, Radioactive; D007856:Lead Radioisotopes; D011868:Radioisotopes; D017687:Radon Daughters; D011886:Radon